QUENCH-14, QUENCH-16 and QUENCH-ALISA analysis

Transcription

1 QUENCH-14, QUENCH-16 and QUENCH-ALISA analysis with RELAP5/SCDAPSIM MOD3.5(KIT) and MOD3.5+(KIT) Presenting authors: Olga Dutkiewicz, Krzysztof Marcinkiewicz Co-authors: Hiroshi Madokoro, dr Heinrich Muscher, dr Juri Stuckert Special thanks to: dr Martin Steinbrück, dr Chris Allison

2 Outline 1. Introduction: title, outline, overview. 2. QUENCH-14 analysis with RELAP5/SCDAPSIM MOD3.5. and MOD3.5+ both using M5* oxidation rate. 3. QUENCH-16 analysis with MOD Pre-test calculations for QUENCH-ALISA with MOD3.5. and MOD Post-test calculations for QUENCH-18 / QUENCH-ALISA in MOD Summary and conclusions. 7. Future plans regarding RELAP5/SCDAPSIM MOD References. 9. The end.

3 Overview KIT s QUENCH experiments, using electrically heated simulator rods, and investigating the behavior of materials, for example cladding or absorber, under accidental conditions; QUENCH focuses on oxidation, hydrogen production, melting, coolability; QUENCH-14 and QUENCH-ALISA / 18 both have M5 cladding; QUENCH-16 and QUENCH-ALISA both are air ingress tests.

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5 QUENCH-14 with M5* Cu Mo AL WATER IN Mo Mo Mo Mo WATER OUT W W W ARGON IN W W W W Zr 1 SS W Fiber W W W Mo Mo Mo Fig. QUENCH-14 test bundle. [1] Mo Cu AR 9 01 ARGON OUT QUENCH-14 used M5. In the analysis we use M5 oxidation rates (according to [2]) instead of standard MATPRO Zircaloy oxidation rates. STEAM IN AR IN FAST QUENCH ING WATER Fig. QUENCH-14 nodalisation in RELAP5/SCDAPSIM.

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8 QUENCH-16 In this experiment there was a significant shroud melt at elevations between ~500 and ~700 mm. The shroud failure lead to water leakage in an amount of 7264 g, found post test in the ZrO 2 fiber [3]. Fig. QUENCH-16 bundle cross sections at 530 mm, 550 mm, 630 mm and 650 mm. [3] Fig. 3D QUENCH-16 model representation. The shroud failure, with water leaking from the bundle, is simulated using valves and a pipe of a volume equal to the volume available in the ZrO 2 fiber. Please note that sources and sinks are not drawn here. Fig. QUENCH-16 bundle withdrawn from cooling jacket. [3]

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10 The experiment, over 140 g The simulation, over 85 g

11 ALISA: pre-test In case of QUENCH-ALISA pre-test calculations we did not assume leakage from the shroud, thus the used physical model was simpler, compared to QUENCH-16. Water cooling jacket Right boundary for the cooling jacket Fig. QUENCH-ALISA bundle composition. [5] The boundary conditions according to the Pre-test simulations of QUENCH- ALISA in the frame of the NUGENIA QUESA project [6] presentation from 4th NUGENIA-SARNET TA2.1 Review Meeting. Fig. QUENCH-ALISA model cross-section. Argon cooling jacket Fig. 3D QUENCH-ALISA model, without sources and sinks.

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13 From [6] pre-test calculations:

14 ALISA: post-test in MOD3.5+ The physical model remains the same, the timeline changes. The new timeline: instead of 7300 s, at 7542 s into the experiment the steam flow is set to 0.3 g/s and argon flow to 1.0 g/s; at 7542 s the air flows at 0.2 g/s rate, and thus the air ingress phase begins; at s the quench begins, instead of s - QUENCH-16 case; s is the end of the quenching phase; s is the end of simulation.

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16 Model 1: W(1)=0 at card Model 2: W(1)=1 at card and M5 oxidation rate instead of Zircaloy s oxidation rate.

17 Model 1: W(1)=0 at card Model 2: W(1)=1 at card and M5 oxidation rate instead of Zircaloy s oxidation rate.

18 Summary QUENCH-14 simulation results are satisfying. However, it has been the least challenging experiment to model. The M5* oxidation rate in MOD3.5. gives similar peak value of hydrogen generation rate to the experimental value. QUENCH-16 is an experiment difficult to model, due to several phenomena. Concerning hydrogen production, the air ingress contributed into 5 g produced in re-oxidation of nitrides in claddings and 2 g in shroud; oxidation of melt has given 19 g of H 2 from claddings and 14 g from shroud. Total contribution of claddings in hydrogen production during reflood was 81g [3], in our simulation we have obtained about 85g. The pre-test calculations for QUENCH-ALISA were until 8700s very similar to those presented as JB_SCDAPSIM in [6]. In our simulation we did not have a temperature escalation during air ingress as in [6]. On the other hand our quench phase has been more pronounced. In the post-test calculations for QUENCH-ALISA we have analyzed different oxidation models available in RELAP5/SCDAPSIM. We have used M5* in model 2. The difference between models 1 and 2 is evident. In model 1 quench phase with fast temperature increase may be observed. In model 2 there is a temperature increase in air ingress. The total hydrogen production is bigger for model 1, for model 2 it is about 10 g smaller. Fig. Photo taken yesterday ( ) at the Quench Workshop; Presentation by dr Juri Stuckert Fig. Our post-test QUENCH-ALISA results with model 2.

19 Conclusions RELAP5/SCDAPSIM model for electrically heated rod is a good tool to model QUENCH experiments. At the very beginning, we have compared the results between simulations using resistance calculated by the code and from the table, and those results were almost identical. RELAP5/SCDAPSIM has given very good results for QUENCH-14. In case of air ingress tests: QUENCH-16 and QUENCH-ALISA, the complex reactions between nitrogen and Zircaloy need be introduced to the code, and for that reason nitrogen should be separated from air. Fig. Source: [4] The chemical reaction of Zircaloy with nitrogen, as described in [8], is an exothermic reaction, where Δh is about J/kg Zr. This value translates into such an example: if 6.79% of Zr present in QUENCH-16 bundle reacted with N 2, then the power difference between QUENCH-16 and QUENCH-14, since 8000 s till the quench, would be compensated. Fig. Source: [4]

20 Conclusions There is a need for a quantification of nitride formation during air ingress and energy release due to that process. In QUENCH-16 simulation we did not obtain the temperature measured in the experiment on the shroud. Our shroud (Zircaloy) did not melt, thus its contribution to the hydrogen production was smaller. Concerning hydrogen production from claddings, our result (85g) is very close to the one mentioned in the report (81g) [3]. Modelling of QUENCH-18 seems less challenging than QUENCH- 16, considering the quenching phase. It may be a result of steam being injected together with air in air ingress phase in ALISA. QUENCH-ALISA post-test and pre-test differ notably, due to different timeline. In post-test calculations we managed to apply M5* oxidation rate (model 2). Temperatures from model 2 reach higher values in air ingress phase than those from model 1. Fig. Chemical interactions and formation of liquid phases in a LWR fuel rod bundle with increasing temperature. [7]

21 Future plans Applying all the phenomena observed in QUENCH-16 to RELAP5/SCDAPSIM: nitridation; re-oxidation of the nitrides; melt oxidation.

22 References: [1] J. Stuckert, U. Stegmaier, M. Steinbrück, Results of Severe Fuel Damage Experiment QUENCH-14 with Advanced Rod Cladding M5, KIT Scientific Report 7549, KIT Scientific Publishing, 2010 [2] M. Grosse, Comparison of the high-temperature steam oxidation kinetics of advanced cladding materials, Nuclear Technology vol. 170, , 2010 [3] J. Stuckert, M. Grosse, Z. Hozer, M. Steinbrück, Results of the QUENCH-16 Bundle Experiment on Air Ingress, KIT Scientific Report 7634, KIT Scientific Publishing, 2013 [4] M. Steinbrück, U. Stegmaier, T. Ziegler, Prototypical Experiments on Air Oxidation of Zircaloy-4 at High Temperatures, FZKA 7257, Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft, 2007

23 References: [5] J. Stuckert, QUENCH bundle tests in the framework of the SAFEST and ALISA projects, 4th NUGENIA-SARNET TA2.1 Review Meeting, March 2 3, 2017 [6] T. Hollands, Pre-test simulations of QUENCH-ALISA in the frame of the NUGENIA QUESA project, 4th NUGENIA-SARNET TA2.1 Review Meeting, March 2 3, 2017 [7] P. Hofmann, S. Hagen, G. Schanz, A. Skokan, Chemical Interactions of Reactor Core Materials Up to Very High Temperatures, KfK 4485, Kernforschungszentrum Karlsruhe, January 1989 [8] C. Bals, T. Hollands, New Results of Post-test Calculation of Quench-16 with ATHLET-CD, June 14, 2016, Budapest

24 Thank You for Your attention.